1. Field of the Invention
The present invention concerns a rotating envelope x-ray tube (rotary piston x-ray tube) of the type having a housing with a beam exit window that is transparent to x-ray radiation.
2. Description of the Prior Art
A rotating envelope tube of the above type is, known for example, from DE 103 35 664 B3. In such rotating envelope tubes, an outer casing of the housing has an annular x-ray exit window produced from a material that is transparent for x-rays, cooling fluid circulates in an intermediate space formed between the outer casing and an inner casing permanently connected therewith. Due to centrifugal forces, in particular at high rotation speeds, the cooling fluid exerts a high pressure on the x-ray exit window. The maximum rotation speed and thus also the load capacity of the rotating envelope tube are limited, among other things, by the stability (strength) of the x-ray exit window.